Fan

ABSTRACT

A fan includes a casing and a fan blade. The casing has at least one air inlet and an air outlet. The fan blade is disposed in the casing. An air flow compression area is defined in the casing. An auxiliary air inlet is disposed on the casing at the air flow compression area. Furthermore, another fan includes a casing and a fan blade. The casing has an upper casing, a lower casing and a side casing located between the upper casing and the lower casing. The upper casing or the lower casing has at least one air inlet, and the side casing has an air outlet. The fan blade is disposed in the casing. An internal space of the casing is defined as an air flow compression area. An auxiliary air inlet is disposed on the casing at the air flow compression area.

This non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No(s). 201210427485.3 filed in China, P.R.C. on Oct. 31, 2012, the entire contents of which are hereby incorporated by reference.

BACKGROUND

1. Technical Field

The disclosure relates to a fan, and more particularly to a fan with an increased exhaust volume.

2. Related Art

With the constant development of technology, current development of daily necessities is toward digitization and informatization. For example, a portable computing device, such as a notebook computer and a tablet computer, is easily carried by a user, so as to be freely used by the user in any occasions.

Furthermore, a set of heat dissipation fins and a fan are generally disposed in the portable computing device, which are used for removing heat generated by the portable computing device. However, as the performance of the portable computing device constantly improves, heat generated during the operation of the portable computing device increases correspondingly. Therefore, usually the heat dissipation area of the heat dissipation fins and the power of the fan are increased, so as to improve the heat removal rate of the portable computing device.

Moreover, to cater to the development trend of the portable computing device toward a thin structure, the fan disposed in the portable computing device is normally designed to be thinner. Generally, a casing of a fan comprises an upper casing and a lower casing opposite to each other, and a side casing connected between the upper casing and the lower casing. The fan has an air outlet located at the side casing thereof, and has an air inlet located at the upper casing or the lower casing thereof.

However, due to the thin structure of the portable computing device, gaps between the housing of the portable computing device and the upper casing and the lower casing of the fan are shortened. Therefore, an air flow flowing into the air inlet of the fan is reduced so that the exhaust volume of the fan is reduced. Consequently, the system's heat dissipation efficiency of the portable computing device is lowered.

SUMMARY

One embodiment of the disclosure provides a fan comprising a casing and a fan blade. The casing has at least one air inlet and an air outlet. The fan blade is disposed in the casing. An air flow compression area is defined in the casing. An air flow pressure in the air flow compression area is lower than the atmospheric pressure outside the casing. The casing has an auxiliary air inlet disposed at the air flow compression area

Another embodiment of the disclosure provides a fan comprising a casing and a fan blade. The casing comprises an upper casing, a lower casing, and a side casing. The side casing is located between the upper casing and the lower casing. The upper casing or the lower casing has at least one air inlet. The side casing has an air outlet. The fan blade is disposed in the casing. A first point is defined at a position of the side casing which is closest to an axle center of the fan blade. A second point is defined at a position of the side casing which is farthest from the air outlet. A connecting line from the first point to the axle center of the fan blade and a connecting line from the second point to the axle center of the fan blade form an included angle. An internal space of the casing covered by the included angle is defined as an air flow compression area. An auxiliary air inlet is disposed on the casing at the air flow compression area

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure will become more fully understood from the detailed description given herein below for illustration only, and thus are not limitative of the disclosure, and wherein:

FIG. 1 is a perspective view of a fan according to one embodiment of the disclosure;

FIG. 2 is a top view of a fan according to one embodiment of the disclosure;

FIG. 3 is a perspective view of a fan according to another embodiment of the disclosure; and

FIG. 4 is a perspective view of a fan according to still another embodiment of the disclosure.

DETAILED DESCRIPTION

The detailed features and advantages of the disclosure are described below in great detail through the following embodiments, the content of the detailed description is sufficient for those skilled in the art to understand the technical content of the present disclosure and to implement the disclosure there accordingly. Based upon the content of the specification, the claims, and the drawings, those skilled in the art can easily understand the relevant objectives and advantages of the disclosure.

Referring to FIG. 1 and FIG. 2, FIG. 1 is a perspective view of a fan according to one embodiment of the disclosure, and FIG. 2 is a top view of a fan according to one embodiment of the disclosure.

A fan 10 of this embodiment is applicable to a heat dissipation system of a portable computing device, so as to improve the system's heat dissipation efficiency of the portable computing device. In this embodiment and some embodiments, the portable computing device may be a notebook computer or a tablet computer, but not limitative of the disclosure. The fan 10 may be a centrifugal fan or other suitable fan, but the disclosure is not limited thereto.

The fan 10 comprises a casing 11 and a fan blade 12.

The casing 11 comprises an upper casing 111, a lower casing 112, and a side casing 113 located between the upper casing 111 and the lower casing 112. Specifically, the upper casing 111 and the lower casing 112 are disposed opposite to each other and separated by a distance. The side casing 113 is connected between the upper casing 111 and the lower casing 112. The upper casing 111, the lower casing 112, and the side casing 113 together form an accommodation space 114. Furthermore, in this embodiment, the upper casing 111 has an air inlet 1111, the lower casing 112 has an air inlet 1121, and the side casing 113 has an air outlet 1131. It should be noted that the number of the air inlets 1111 and 1121 is not intended to limit the disclosure. For example, in other embodiments, only the upper casing 111 has the air inlet 1111, and the lower casing 112 does not have the air inlet 1121; or, only the lower casing 112 has the air inlet 1121, and the upper casing 111 does not have the air inlet 1111.

In this embodiment, the fan blade 12 is rotatably (namely, in a rotatable manner) disposed in the casing 11. Specifically, the fan blade 12 is rotatably disposed in the accommodation space 114 formed by the upper casing 111, the lower casing 112, and the side casing 113 together.

In this embodiment, the side casing 113 further comprises a curved line segment 1133 and two straight line segments 1134 and 1135 connected to two opposite ends of the curved line segment 1133. The air outlet 1131 is located between the two straight line segments 1134 and 1135. Specifically, the curved line segment 1133 surrounds the fan blade 12, and the distance between the curved line segment 1133 and an axle center 121 gradually increases along a clockwise direction. The straight line segment 1135 is connected to one end (the right end in the drawing) of the curved line segment 1133, and the straight line segment 1135 extends along a tangential direction at one end (the right end in the drawing) of the curved line segment 1133. Furthermore, the straight line segment 1134 extends from the other end (the left end in the drawing) of the curved line segment 1133. The straight line segment 1134 and the curved line segment 1133 are recessed inwards to form an angle, so that a recessed portion 1132 of the side casing 113 is formed at the junction of the straight line segment 1134 and the curved line segment 1133.

A first point P1 is defined at a position of the side casing 113 which is closest to the axle center 121 of the fan blade 12. The first point P1 is located at the recessed portion 1132. A second point P2 of the side casing 113 is defined at a position which is farthest from the air outlet 1131. The second point P2 is located in the middle part of the curved line segment 1133. Furthermore, a connecting line L1 from the first point P1 to the axle center 121 of the fan blade 12 and a connecting line L2 from the second point P2 to the axle center 121 of the fan blade 12 form an included angle θ together. The included angle θ may be, but not limited to, an obtuse angle. Covered by the included angle θ, and an internal space of the casing 11 is defined as an air flow compression area 1141. Specifically, the internal space of the casing 11, covered by a sector-shaped area having a center point being the axle center 121 as well as extending outwards along the connecting line L 1 and the connecting line L2, is the air flow compression area 1141.

Furthermore, the casing 11 has an auxiliary air inlet 115 at the air flow compression area 1141. In this embodiment, the auxiliary air inlet 115 is located on the side casing 113 (as shown in FIG. 1).

Given that the air flow tends to flow from a high air pressure region to a low air pressure region, the casing 11 has the auxiliary air inlet 115 at the air flow compression area 1141 has a flow guiding function when the fan 10 is disposed in the housing (not shown) of a portable computing device as well as gaps between the housing (not shown) of the portable computing device and the upper casing 111 and the lower casing 112 of the fan 10 are narrow. Thus, when the fan blade 12 rotates, outside air is guided into the fan 10 through the auxiliary air inlet 115 at the side casing 113, so as to increase the overall exhaust volume of the fan 10. Therefore, the system's heat dissipation efficiency of the portable computing device using the fan 10 is improved.

Furthermore, according to actual experimental measurement, a conventional fan without auxiliary air inlet has an exhaust volume of 2.03 cubic feet per minute (CFM). By comparison, the exhaust volume is 2.41 CFM when the auxiliary air inlet 115 is added to the fan. According to the above data, the air flow of the fan 10 provided with the auxiliary air inlet 115 in this embodiment is increased by 18.7% when compared with the air flow of a conventional fan. Therefore, the fan 10 of this embodiment surely may improve the system's heat dissipation efficiency of the portable computing device.

Referring to FIG. 3, FIG. 3 is a perspective view of a fan according to another embodiment of the disclosure. This embodiment is similar to the embodiment of FIG. 1, and only differences are illustrated.

In this embodiment, the auxiliary air inlet 115 of the fan 10 a is located the upper casing 111 of the casing 11 at the air flow compression area 1141. Therefore, when the fan blade 12 rotates, outside air is guided into the fan 10 a through the auxiliary air inlet 115 at the upper casing 111, so as to increase the overall exhaust volume of the fan 10 a.

Referring to FIG. 4, which is a perspective view of a fan according to still another embodiment of the disclosure. This embodiment is similar to the embodiment of FIG. 1, and only differences are illustrated.

The auxiliary air inlet 115 of the fan 10 b of this embodiment is located on the lower casing 112 of the casing 11 at the air flow compression area 1141. Therefore, when the fan blade 12 rotates, outside air is guided into the fan 10 b through the auxiliary air inlet 115 at the lower casing 112, so as to increase the overall exhaust volume of the fan 10 b.

According to the fan of the above embodiments, when the gaps between the housing of the portable computing device and the upper casing and the lower casing of the fan are narrow, the auxiliary air inlet is disposed on the casing at the air flow compression area, so as to provide a flow guiding function. Therefore, when the fan blade rotates, outside air is guided into the fan through the auxiliary air inlet, so as to increase the overall exhaust volume of the fan. As a result, the system's heat dissipation efficiency of the portable computing device using the fan is improved.

The foregoing description of the exemplary embodiments of the disclosure has been presented only for the purposes of illustration and description and is not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. Many modifications and variations are possible in light of the above teaching.

The embodiments were chosen and described in order to explain the principles of the disclosure and their practical application so as to activate others skilled in the art to utilize the disclosure and various embodiments and with various modifications as are suited to the particular use contemplated. Alternative embodiments will become apparent to those skilled in the art to which the disclosure pertains without departing from its spirit and scope. Accordingly, the scope of the disclosure is defined by the appended claims rather than the foregoing description and the exemplary embodiments described therein. 

What is claimed is:
 1. A fan, comprising: a casing having at least one air inlet and an air outlet; and a fan blade disposed in the casing, wherein an air flow compression area is defined in the casing, an air flow pressure in the air flow compression area is lower than the atmospheric pressure outside the casing, and the casing has an auxiliary air inlet disposed at the air flow compression area.
 2. The fan according to claim 1, wherein the casing comprises an upper casing, a lower casing, and a side casing located between the upper casing and the lower casing, the upper casing and the lower casing respectively have the air inlet, and the air outlet is located at the side casing.
 3. The fan according to claim 1, wherein the casing comprises an upper casing, a lower casing, and a side casing located between the upper casing and the lower casing; a first point is defined at a position of the side casing which is closest to an axle center of the fan blade, a second point is defined at a position of the side casing which is farthest from the air outlet; a connecting line from the first point to the axle center of the fan blade and a connecting line from the second point to the axle center of the fan blade form an included angle, and an internal space of the casing covered by the included angle is defined as the air flow compression area.
 4. The fan according to claim 3, wherein the auxiliary air inlet is located on at least one of the upper casing, the lower casing, and the side casing.
 5. The fan according to claim 3, wherein the side casing comprises a curved line segment and two straight line segments connected to two opposite ends of the curved line segment, the curved line segment surrounds the fan blade, and the air outlet is located between the two straight line segments.
 6. A fan, comprising: a casing comprising an upper casing, a lower casing, and a side casing located between the upper casing and the lower casing, the upper casing or the lower casing having at least one air inlet, and the side casing having an air outlet; and a fan blade disposed in the casing, wherein a first point is defined at a position of the side casing which is closest to an axle center of the fan blade, a second point is defined at a position of the side casing which is farthest from the air outlet, a connecting line from the first point to the axle center of the fan blade and a connecting line from the second point to the axle center of the fan blade form an included angle; an internal space of the casing covered by the included angle is defined as an air flow compression area; and an auxiliary air inlet is disposed on the casing at the air flow compression area.
 7. The fan according to claim 6, wherein the upper casing and the lower casing have the air inlet respectively.
 8. The fan according to claim 6, wherein an air flow pressure in the air flow compression area is lower than the atmospheric pressure outside the casing.
 9. The fan according to claim 6, wherein the auxiliary air inlet is located on at least one of the upper casing, the lower casing, and the side casing.
 10. The fan according to claim 6, wherein the side casing comprises a curved line segment and two straight line segments connected to two opposite ends of the curved line segment, the curved line segment surrounds the fan blade, and the air outlet is located between the two straight line segments. 